It's a graphic illustration of the changing face of our streets over the second half of the 20th century.

These pictures show how many of the areas around of homes have been transformed from popular play areas for local children to car-dominated no-go areas.

The photographs, dating from the 1940s to the present, paint a stark contrast with children and families enjoying the freedom of the streets in days gone by, and largely banished in the most recent images.

They have been collated by sustainable transport charity Sustrans Cymru as part of a campaign to encourage children to cycle to school.

Lee Waters, national director in Wales for Sustrans, claimed forced change in behaviour has likely contributed to the rise in childhood obesity in Wales.

As more of us take to our cars more often, he claims, so the perception increases that the only safe way to get our children around is to place them within the security of a car’s steel frame.

Mr Waters said reversing this trend will take a combination of steps.

Over the past three weeks schoolchildren around the country have been taking part in Big Pedal, a Sustrans-organised scheme to encourage children to cycle to school.

Last year more than 950 schools around Wales took part. Across the UK as a whole children cycled a total of 1,140,075 miles during the three-week scheme, saving 59,021 gallons of fuel and £368,484.

Malcolm Shepherd, Sustrans’ UK chief executive, said: “The average primary school journey is just 1.5 miles – the perfect distance to walk or cycle.

“Every year The Big Pedal helps tens of thousands of families rediscover the fun and freedom of cycling to school, get fit and save money at the same time.

“With the Welsh Government set to introduce the Active Travel Bill, promotions such as the Big Pedal are crucial in helping families discover the safe routes that exist in their communities.

“Evidence shows how children that cycle to school regularly are more active and better learners – it’s time for us all to get on our bikes.”

Last month the Welsh Government set out its plans to encourage people to walk and cycle more around our towns and cities.

The plans, contained within the Active Travel (Wales) Bill, would require local authorities to plan car-free “active travel” networks to create routes safe for walkers and cyclists, and consider walking and cycling provision in new road developments.

These networks could include routes around schools, shopping centres and hospitals which are specifically car-free.

Launching the Bill at Millbank School in Cardiff, local government minister Carl Sergeant said: “We want to make walking and cycling the most natural and normal way of getting about and to ensure that active travel is a viable mode of transport for shorter journeys.

“This will help make Wales a healthier and greener nation.”

The Welsh Conservatives’ shadow transport minister Byron Davies said: “This bill should not be about the nanny state telling people what to do, but about making it easier for people to include exercise in their daily routine.

“As a constructive opposition, Welsh Conservatives will thoroughly scrutinise this legislation and work towards the implementation of a robust strategy to encourage active travel.”

Sustrans Cymru claims the plans have the potential to be as important for public health as the smoking ban in public places, which was introduced in 2007.

Mr Waters said: “The evidence shows that the easiest way for most people to get more exercise is to build it into their daily routine, but even though most everyday journeys are short, many of us still choose to take the car.

“In fact 20% of our car journeys are less than one mile. The Active Travel Bill aims to get more people walking and cycling for short local trips as part of tackling the obesity epidemic and reducing congestion.”

The proposed legislation also received a welcome from the medical profession, with Paul Myres, chairman of the Royal College of General Practitioners in Wales, saying: “As many people die from physical inactivity each year as die from smoking. This bill has the potential to make a real difference in improving the health of our nation.

“Scientific evidence has shown that our sedentary lifestyles are leading to an increase in diseases including diabetes, heart diseases and some cancers and that lack of activity is one of the easiest areas to address for most of us and can reap as much, if not more, benefit than reducing cholesterol in our diet.

“Getting regular exercise every day is crucial, what better way than to build it into the journeys we make on a regular basis.”

The chief medical officer for Wales Dr Ruth Hussey said: “We know our environment and transport can have an impact on our health and I believe the Active Travel Bill will make it easier in everyone in Wales to make healthier choices.

“Small changes to our daily routines, like walking and cycling short distances, can improve the way we feel as well as our physical health.

“By making changes to the environment and transport, the Active Travel Bill will make the healthy choice the easier choice. This is a great step forward for Wales.”